The chemistry of 5-oxodihydroisoxazoles. Part 22.1 The synthesis of 1,3-oxazin-6-ones from N-thioacylisoxazol-5(2H )-ones
作者:David S. Millan、Rolf H. Prager
DOI:10.1039/a804527e
日期:——
N-Thioacylisoxazol-5(2H)-ones, prepared by the reaction of thiocarbonyl chlorides with isoxazol-5(2H)-ones in the presence of base, are reduced by triphenylphosphine to afford 1,3-oxazin-6-ones and triphenylphosphine sulfide. If the thioacylation is carried out with phenyl chlorodithioformate, the thermal rearrangement of the intermediate, to again form the oxazin-6-one and sulfur, is so rapid that the use of the phosphine is not required. The presence of an ethoxycarbonyl group at C-3, or of a bromine atom at C-4 of the isoxazolone results in the formation of thiazoles.
The synthesis of oxazoles by thermolysis or photolysis of 2-acylisoxazol-5-ones
作者:Kiah H. Ang、Rolf H. Prager、Jason A. Smith、Ben Weber、Craig M. Williams
DOI:10.1016/0040-4039(95)02240-6
日期:1996.1
N-acylisoxazol-5-ones are converted into the corresponding 2-substituted oxazoles by photolysis at 300 or 254nm, or by flash vacuum pyrolysis. The former procedure is favoured for isoxazolones with electron withdrawing groups at C-4, and pyrolysis for all others.
Synthesis of adamantane derivatives. LVIII. Reaction of 1-adamantyl chloride with some heterocyclic unsaturated silanes.
作者:TADASHI SASAKI、AKIRA NAKANISHI、MASATOMI OHNO
DOI:10.1248/cpb.30.2051
日期:——
Various silylated heterocycles having amide functionality were treated with 1-adamantyl chloride (1) in the presence of a Lewis acid to give the corresponding N-adamantylated heterocycles. If α-position to the reacting lactim nitrogen was substituted, the reaction no longer occurred, or the adamantylation occurred at the position other than the expected nitrogen. These facts are attributed to a steric blocking effect of the α-substituent. While the same treatment of the thioamide 46 gave the S-adamantylated product, 48 and 51 afforded in contrast the N- and S-adamantylated products, respectively ; this result can be explained in terms of steric effect. Analogously, silylated 2-pyrazolines and triazoles were adamantylated at nitrogen. The reactions of 2-trimethylsilylthiophene, furan and -pyridine with 1 failed to give site-selective monoadamantylation.
Investigation on the reactivity of isoxazol-5-ones towards 1,2-diaza-1,3-dienes: new entry to variously substituted (imidazol-2-yl)acetate and 1,3-oxazin-6-one derivatives
作者:Orazio A. Attanasi、Silvia Bartoccini、Gianfranco Favi、Gianluca Giorgi、Francesca R. Perrulli、Stefania Santeusanio
DOI:10.1016/j.tet.2011.10.118
日期:2012.1
derivative. The first aza-Michael addition is followed by an intramolecular second, affording a fused heterobicyclic system that, upon ring opening and decarboxylation processes, gives rise to novel substituted imidazoles with an acetate functionality in the 2-position. On the contrary, under the same reaction conditions, 3-phenylisoxazol-5-one provides a double Michael addition at two units of DD involving
Compounds of the formula ##STR1## wherein R is phenyl or phenyl substituted with 1 to 3 of the same or different substituents selected from fluoro, chloro, bromo, iodo, nitro, lower alkyl, lower alkoxy or lower alkyl substituted with 1 to 3 of the same or different halogens; and R.sup.1 is lower alkyl are good fungicides.